EP1654559B1 - Verfahren zur erzeugung von taktkorrekturen für ein grossflächiges oder globales differenz-gps-system - Google Patents

Verfahren zur erzeugung von taktkorrekturen für ein grossflächiges oder globales differenz-gps-system Download PDF

Info

Publication number
EP1654559B1
EP1654559B1 EP04816780A EP04816780A EP1654559B1 EP 1654559 B1 EP1654559 B1 EP 1654559B1 EP 04816780 A EP04816780 A EP 04816780A EP 04816780 A EP04816780 A EP 04816780A EP 1654559 B1 EP1654559 B1 EP 1654559B1
Authority
EP
European Patent Office
Prior art keywords
reference station
master
satellite
local
computing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP04816780A
Other languages
English (en)
French (fr)
Other versions
EP1654559A2 (de
Inventor
Richard T. Sharpe
Ronald R. Hatch
Frederick W. Nelson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NavCorn Technology Inc
Original Assignee
NavCorn Technology Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NavCorn Technology Inc filed Critical NavCorn Technology Inc
Publication of EP1654559A2 publication Critical patent/EP1654559A2/de
Application granted granted Critical
Publication of EP1654559B1 publication Critical patent/EP1654559B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/03Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers
    • G01S19/07Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers providing data for correcting measured positioning data, e.g. DGPS [differential GPS] or ionosphere corrections
    • G01S19/072Ionosphere corrections
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/38Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
    • G01S19/39Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/40Correcting position, velocity or attitude
    • G01S19/41Differential correction, e.g. DGPS [differential GPS]

Definitions

  • the present invention relates generally to positioning and navigation systems that use the Global Positioning System (GPS), and particularly to methods of computing satellite clock corrections for wide area or global differential GPS (DGPS) networks.
  • GPS Global Positioning System
  • DGPS global differential GPS
  • GPS uses satellites in space to locate objects on earth. With GPS, signals from the satellites arrive at a GPS receiver and are used to determine the position of the GPS receiver.
  • the two types of GPS measurements are pseudorange, and integrated carrier phase for two carrier signals, L1 and L2, with frequencies of 1.5754 GHz and 1.2276 GHz, or wavelengths of 0.1903 m and 0.2442 m, respectively.
  • Some receivers output a Doppler measurement which is simply the difference in two consecutive integrated carrier phase measurements.
  • the pseudorange measurement (or code measurement) is a basic GPS observable that all types of GPS receivers can make.
  • the measurement records the apparent time taken for the relevant code to travel from the satellite to the receiver, i.e. the time the coded signal left the satellite according to the satellite clock minus the time it arrives at the receiver according to the receiver clock.
  • the carrier phase measurement is obtained by integrating a reconstructed carrier of the coded signal as it arrives at the receiver.
  • the carrier phase measurement is also a measure of a transit time difference as determined by the time the signal left the satellite according to the satellite clock and the time it arrives at the receiver according to the receiver clock.
  • the transit time difference may be in error by the periods of a few carrier cycles, i.e. there is a whole-cycle ambiguity in the carrier phase measurement.
  • the carrier frequencies are much higher and their pulses are much closer together than those of the C/A or P codes, the carrier phase measurement can be much more accurate than the code measurement.
  • the code measurements are affected much more than the carrier phase measurements by the interference of reflected signals with the direct signal. This interference also causes the code measurements to be less accurate than the carrier phase measurements.
  • the range or distance between a GPS receiver and a satellite is calculated by multiplying a signal's travel time by the speed of light.
  • These ranges are usually referred to as pseudoranges (false ranges) because the receiver clock generally has a significant time error which causes a common bias in the measured range.
  • This common bias from receiver clock error is solved for along with the position coordinates of the receiver as part of the normal navigation computation.
  • Various other factors can lead to errors or noise in the calculated range, including ephemeris error, satellite clock timing error, atmospheric effects, receiver noise and multipath error.
  • differential operations are typically used in GPS applications to cancel the noise factors in the pseudorange and/or carrier phase measurements resulting from these error sources.
  • Differential GPS (DGPS) operations typically involve a base reference GPS receiver, a user GPS receiver, and a communication mechanism between the user and reference receivers.
  • the reference receiver is placed at a known location and the known position is used to generate corrections associated with some or all of the above error factors.
  • the corrections are supplied to the user receiver and the user receiver then uses the corrections to appropriately correct its computed position.
  • the corrections can be in the form of corrections to the reference receiver position determined at the reference site or in the form of corrections to the specific GPS satellite clock and/or orbit. Corrections to the reference receiver position are not as flexible because, for optimum accuracy, they require that the same satellites be observed by the user receiver and the reference receiver.
  • DGPS Differential GPS
  • the atmospheric effects are due to the GPS signal passing through the charged particles of the ionosphere and then through the water vapor in the troposphere.
  • the effect of the ionosphere on the GPS signal is usually modeled by an ionospheric refraction model and errors in the model contribute to errors in the computed range. These errors are strongly correlated between the reference and user receivers over short distances between the two receivers, but the correlation diminishes over large distances.
  • Refraction of the GPS signal in the troposphere can generally be modeled to remove 90 to 95 percent of the tropospheric effects.
  • the residual tropospheric errors can be reduced by the use of a DGPS when the user does not roam across large distances, because the correlation of tropospheric refraction error typically disappears as soon as the user is a few tens of kilometers away from the reference receiver. So the use of the DGPS by itself does not produce meaningful reductions of the residual tropospheric refraction error. Sometimes, the uncorrelated error at the reference receiver can even worsen the situation by introducing additional error into the computed user position.
  • the ephemeris or satellite orbital error can be modeled as having along-track, cross track, and radial error vectors.
  • the satellite orbital error can be reduced by using the DGPS system.
  • the reduction is somewhat limited because the correlation in the satellite orbital error gradually reduces as the separation between the reference and user receivers increases. The correlation is largely diminished over continental distances.
  • Receiver noise and multipath (reflected signal) effects are generally uncorrelated between the reference and user receivers. These error effects are sometimes amplified by the use of DGPS systems.
  • the WADGPS includes a network of multiple reference stations in communication with a computational center or hub. Error corrections are computed at the hub based upon the known locations of the reference stations and the measurements taken by them. The computed error corrections are then transmitted to users via a communication link such as satellite, phone, or radio.
  • raw data such as the measurements and positions of the reference receivers are supplied to the user receiver(s) rather than the corrections.
  • the user receiver can select the data from a particular reference station or form corrections from a weighted combination of the data from the multiple reference stations.
  • WADGPS provides more accurate estimates of the error corrections.
  • the use of multiple reference stations also makes computation of the error corrections more complicated and different error factors can alias into each other, destroying the correlations inherent in the GPS measurements.
  • US 5,621,646 describes a wide area differential GPS reference system that includes a pseudo-range residual synchronizer that is responsive to received pseudo-range residuals in order to compute clock differences between reference stations and remove clock differences from the received pseudo-range residual so as to synchronize them.
  • the present invention includes a method for generating satellite clock corrections for a wide area differential GPS (WADGPS) network.
  • WADGPS wide area differential GPS
  • the WADGPS network includes a plurality of reference stations each having a dual-frequency GPS receiver, which facilitates obtaining GPS measurements, including pseudorange code measurements and carrier phase measurements, on both the L1 and L2 carrier signals.
  • ionospheric refraction effects can be completely removed from the GPS measurements taken at the reference stations.
  • a linear combination of carrier-phase measurements can be formed to match the ionospheric refraction effects of the corresponding code measurements.
  • the removal of the ionospheric refraction effects or the difference between the ionospheric refraction effects on the code measurements and on the corresponding carrier phase measurements allows unlimited smoothing of the code measurements with the corresponding carrier-phase measurements. This in turn allows a virtual elimination of multipath noise after smoothing for a certain period of time, such as ten minutes or more. Satellite orbital errors, because they change much more slowly, can either be removed in a separate computational process when the WADGPS network is a global DGPS network, or can simply be ignored when the WADGPS network is for a continential sized region.
  • the tropospheric refraction effect can be largely removed by modelling, and if desired, can be improved by the use of small stochastic adjustments included in the computation of the clock correction.
  • satellite clock corrections are computed for the individual reference stations.
  • An average clock correction is formed thereafter for each of a plurality of satellites by taking an average or weighted average of the satellite clock corrections over reference stations to which the satellite is visible.
  • the method of the present invention computes satellite clock corrections after the removal of all other substantial error components, the method can be strikingly simple and very robust as compared to conventional methods, which often employ Kalman filters to solve for many different parameters simultaneously.
  • the disadvantage of these conventional methods is that various error sources can alias into one another and destroy the perfect correlation inherent in the satellite clock errors.
  • FIG. 1 is a block diagram of a WADGPS network according to one embodiment of the present invention.
  • FIG. 2A is a block diagram of a computer system that serves as an example of a main computer system in the WADGPS network according to one embodiment of the present invention.
  • FIG. 2B is a block diagram of a computer system at a reference station in the WADGPS network according to one embodiment of the present invention.
  • Figure 3A is a flowchart illustrating a method for forming a smoothed refraction-corrected code measurement according to one embodiment of the present invention.
  • Figure 3B is a flowchart illustrating a method for smoothing the refraction-corrected code measurement according to one embodiment of the present invention.
  • Figure 3C is a flowchart illustrating a method for smoothing the refraction-corrected code measurement according to an alternative embodiment of the present invention.
  • Figure 4A is a flowchart illustrating a method for computing satellite clock corrections for the WADGPS network according to one embodiment of the present invention.
  • Figure 4B is a flowchart illustrating a method for computing satellite clock corrections for the WADGPS network according to an alternative embodiment of the present invention.
  • Figure 4C is a flowchart illustrating a method for computing satellite clock corrections for the WADGPS network according to another alternative embodiment of the present invention.
  • Figure 4D is a flowchart illustrating a method for computing satellite clock corrections for the WADGPS network according to yet another alternative embodiment of the present invention.
  • FIG. 1 illustrates a wide-area or global DGPS (WADGPS) system 100.
  • the WADGPS network 100 includes a plurality of satellites 110, a plurality of reference stations 120 each having a GPS receiver 122, and communication links (not shown) among the satellites 110 and the reference stations 120.
  • the reference stations 120 are placed at known locations across a wide area 101, such as a continent, for a wide-area DGPS system, or across the globe for a global DGPS network
  • the WADGPS network 100 may be utilized by one or more users 140 each having a user GPS receiver 142 for positioning and/or navigation purposes.
  • the WADGPS system 100 further includes a main computer system (not shown in FIG. 1 ) that is shared among the reference stations.
  • the main computer system can be located at one of the reference stations or at a different place in or near the area 101.
  • FTG. 2A shows a block diagram of an exemplary computer system 200 that can be used to as the main computer system Referring to FIG. 2A , the computer system 200 can be a microprocessor-based computer coupled via the internet and/or various other communication links to the reference stations 120.
  • Computer system 200 includes a central processing unit (CPU) 202, memory 210, a multitude of input ports 204 and an output port 206, and (optionally) a user interface 208, coupled to each other by one or more communication buses 209.
  • CPU central processing unit
  • the memory 210 may include high-speed random access memory and may include nonvolatile mass storage, such as one or more magnetic disk storage devices. Memory 210 may include mass storage that is remotely located from the central processing unit 202.
  • the memory 210 preferably stores an operating system 212, a database 214, and GPS application procedures 216, including procedures 218 for implementing methods of generating satellite clock corrections in the embodiments of the present invention, as described in more detail below.
  • the operating system 212 and application programs and procedures 216 and 218 stored in memory 210 are for execution by the CPU 202 of the computer system 200.
  • the memory 210 preferably also stores data structures used during execution of the GPS application procedures 216 and 218, including the smoothed refraction corrected code measurements and mean receiver clock errors associated with individual reference stations as described below, as well as other data structures discussed in this document.
  • the operating system 212 may be, but is not limited to, an embedded operating system, UNIX, Solaris, or Windows 95, 98, NT 4.0, 2000 or XP. More generally, operating system 212 has procedures and instructions for communicating, processing, accessing and storing data, and for performing other basic operations.
  • the input ports 204 are for receiving data from the reference stations 120, and output port 206 is used for outputting data and/or calculation results. Data and calculation results may also be shown on a display device of the user interface 208.
  • GPS measurement data taken at the reference stations are sent to the input ports 204 of the computer system 200 for processing by the computer system 200 according the procedures 218, as described in more detail below.
  • Calculation results are output through the output port 206 of the computer system 200 and are sent via redundant communication links to an upload station among the reference stations 220.
  • the upload station sends the correction data to one or more of the satellites 210 for broadcast to the user 240.
  • the computer system 200 usually includes a very high-speed processor since it may need to handle raw GPS measurement data from a multitude of GPS receivers.
  • a continental WADGPS system usually has about 3 to 10 reference receivers and a global WADGPS system usually has about 20 to 100 reference receivers feeding data to the computer system 200.
  • each of the reference stations 120 may include a computer system 124 coupled to the GPS receiver 122.
  • a computer system 124 coupled to the GPS receiver 122 at a reference station 120 includes a central processing unit (CPU) 126, memory 128, and an input port 134 and an output port 136, and (optionally) a user interface 138, coupled to each other by one or more communication buses 129.
  • the memory 128 may include high-speed random access memory and may include nonvolatile mass storage, such as one or more magnetic disk storage devices.
  • the memory 128 preferably stores an operating system 131, a database 133, and GPS application procedures 135.
  • the GPS application procedures may include procedures 137 for implementing methods of forming smoothed refraction corrected code measurements in the embodiments of the present invention, as described in more detail below.
  • the operating system 131 and application programs and procedures 135 and 137 stored in memory 128 are for execution by the CPU 126 of the computer system 124.
  • the memory 128 preferably also stores data structures used during execution of the GPS application procedures 135 and 137, including GPS pseudorange and carrier-phase measurements 139, as well as other data structures discussed in this document.
  • the input port 134 is for receiving data from the GPS receiver 122, and the output port 136 is used for outputting data and/or calculation results to the main computer system 200 of the WADGPS system. Data and calculation results may also be shown on a display device of the user interface 138.
  • the CPU 126, the memory 128 and the input port 134 of the computer system 124 are integrated with the GPS receiver 122 into a single device, within a single housing, as shown by the dashed line in FIG. 2B . However, such integration is not required to carry out the methods of the present invention.
  • satellite clock corrections are computed using smoothed refraction-corrected code measurements associated with one or more reference stations. For each of the one or more reference stations, the smoothed refraction-corrected code measurements are formed at each measurement epoch from the pseudorange and carrier phase measurements taken by the GPS receiver at the reference station.
  • Many GPS receivers make both a C/A-code measurement and a P-code measurement on the L1 or L2 frequency, and either of the C/A or P-code measurements can be used as the L1 or L2 code measurement.
  • small biases exist between the two measurements whichever of the two is used in the reference receiver, the same should also be used for the equivalent process in the user GPS receiver(s).
  • the L1 and L2 frequencies will be designated as f 1 and f 2 , respectively
  • the raw pseudorange code measurements on the L1 and L2 frequencies at a measurement epoch will be designated as P 1 and P 2 , respectively
  • the raw carrier phase measurement on the L1 and L2 frequencies at the same measurement epoch will be designated as ⁇ 1 and ⁇ 2 .
  • FIG. 3A illustrates a method 300 for obtaining a smoothed, refraction-corrected code measurement from GPS data taken at a reference station.
  • method 300 includes step 310 in which the raw code and carrier-phase measurements for each satellite visible at the reference station are first refraction corrected to obtain refraction corrected code and carrier-phase measurements.
  • L 1 ⁇ 1 + N 1 ⁇ ⁇ 1
  • L 2 ⁇ 2 + N 2 ⁇ ⁇ 2 , where the whole-cycle values of N 1 and N 2 have been initialized at the start of carrier-phase tracking to give values that are within one carrier wavelength of the corresponding code measurements so as to keep the differences between the scaled carrier-phase measurements and the corresponding code measurements small.
  • equation (2) it is noted that the refraction corrected carrier-phase measurement includes a whole-cycle ambiguity with a wavelength determined by the sum of the f 1 and f 2 frequencies, which is approximately 0.1070 meters.
  • the values of P RC and L RC obtained in step 310 should be almost identical except for the possible whole-cycle ambiguity associated with the carrier-phase measurements and the higher multipath noise in the code measurements. This allows the formation of a carrier-phase smoothed code measurement, which approaches the small measurement noise of the carrier-phase but without the associated whole-cycle ambiguity.
  • method 300 further includes step 320 in which the refraction corrected code measurement is smoothed by the corresponding refraction corrected carrier-phase measurement. As shown in FIG. 3B , step 320 is performed in two substeps, substep 322 and substep 324.
  • an offset between the refraction corrected code measurement and the refraction corrected carrier-phase measurement at each of a series of measurement epochs is computed and an expanding average is taken to form a smoothed offset O l as follows:
  • O i O i - 1 + P RC i - L RC i - O i - 1 / ⁇ , where i is used to designate the current measurement epoch, and the value of ⁇ is equal to i until a maximum value of averaging is attained
  • the carrier-phase measurement is assumed to have only 1/100 th of the noise of the code measurement, the value of " ⁇ " would be limited to 100 squared or 10,000.
  • the two-step process for performing step 320 as described above can be combined into a single-step, so that: where This single step process projects the measurement ahead using the change in the refraction corrected carrier-phase measurement and then averages the difference between that projection and the code measurement.
  • the two-step process has an advantage in that the constancy of the offset value can be monitored and, if desired, a threshold change in the value can be used to edit out erroneous measurements.
  • FIG. 3C illustrates another method 350 for obtaining the smoothed refraction-corrected code measurements from GPS data obtained at a reference station.
  • method 350 includes step 360 in which a linear combination of L 1 and L 2 for each satellite is formed to match the ionospheric refraction effects on each of the code measurements P 1 and P 2 .
  • the value of the smoothed refraction-corrected code measurement obtained using equation (7) from the first method is mathematically equivalent to the value of the smoothed refraction-corrected code measurement obtained using equation (13) from the second method.
  • any edit threshold used for the change in the refraction corrected offset in equation (5) must be larger than a corresponding edit threshold of equation (10).
  • the calculation of the theoretical range may include an adjustment or corrections for the tropospheric refraction effects computed based on a theoretical model for the tropospheric refraction effects.
  • the theoretical range may also include adjustment or corrections for the satellite orbital errors. These corrections may be computed in a separate or off-line module. They may also be computed less frequently than the computation of clock corrections.
  • a master station is selected among a group of reference stations including some or all of the reference stations in the WADGPS network.
  • the master reference station can be selected based on a judgment that its clock is the most accurate among the group of reference stations, or a determination that it has measurements available from the largest number of satellites among the group of reference stations, or some combined function of these or other factors, or even arbitrarily.
  • the reference stations other than the master reference station are referred to below as local reference stations.
  • FIG. 4A illustrates a method 400 for generating satellite clock corrections for the WADGPS network 200.
  • method 400 includes step 410 in which satellite clock corrections are computed at the current measurement epoch i for the master reference station.
  • the satellite clock corrections are expressed in terms of distance for application as direct corrections to the measured ranges.
  • Method 400 further includes step 420 in which satellite clock corrections are computed at the current measurement epoch i for one or more local reference stations each having at least one common satellite with the master reference station.
  • a reference station has a common satellite with another reference station, or the satellite is common to both of the reference stations, when both of the reference stations have GPS measurements available from the satellite to form the smoothed refraction-corrected code measurements for the satellite at the current measurement epoch as described above.
  • Equation (18) The summation in Equation (18) is over satellites common to the master reference station and the reference station k , and m k represents the number of such satellites.
  • method 400 further includes step 430 in which an average clock correction is computed for every satellite visible either at the master reference station or visible at some or all of the local reference stations having one or more common satellites with the master reference station.
  • FIG. 4B illustrates a method 450 for generating satellite clock corrections for the WADGPS network 200.
  • the satellite clock corrections are computed iteratively.
  • Equations (17) and (18) are computed for each of a subgroup of local reference stations, and the average in Equation (19) is over the master reference station and the subgroup of local reference stations.
  • the subgroup of local reference stations originally includes no reference station and a local reference station is added to the subgroup of local reference stations in each iteration.
  • method 450 includes step 455 in which satellite clock corrections are computed for the master reference station according to Equations (15) and (16).
  • Method 450 then proceeds to step 460 in which a first local reference station is added to the subgroup of local reference stations.
  • the first local reference station is preferably a local reference station having the most number of common satellites with the master reference station.
  • Method 450 then proceeds to step 470 in which satellite clock corrections are computed for the first local reference station using Equations (15) through (18), and to step 480 in which average clock corrections.are computed by averaging the satellite clock corrections computed for the master reference station and the first local reference station using Equation (19).
  • method 450 goes back to step 460 to add one of these other local reference stations to the subgroup of local reference stations.
  • a reference station sharing the next largest number of common satellites with the master reference station is selected.
  • method 450 proceeds to perform the calculations in step 470 and 480 for the new subgroup using equations (17) through (19) except that the term r 0 l in Equation (18) is replaced by c l computed using Equation (19) in step 470 in the previous iteration.
  • the iteration continues until all of the local reference stations sharing common satellites with the master reference station have been included in the subgroup of local reference stations and average clock corrections are calculated considering the subgroup of local reference stations.
  • Equations (17) through (19) are especially useful for a global DGPS network because a problem can occur in a global DGPS network when there are few if any common satellites visible at both the master reference site and the particular reference site for which satellite clock corrections are being computed. This can cause equation (19) to be either poorly defined or even undefined, and the problem can be overcome by the iteration process in method 450.
  • Method 400 or 450 for generating satellite clock corrections is simple and effective. Various modifications to the method can be made to improve the accuracy of the computed satellite clock corrections without departing from *the scope of the present invention.
  • method 400 or 450 can be modified so that a weighted combination of the satellite clock corrections computed for the individual reference stations is used on the right hand side of Equation (19) to form the average clock correction.
  • the individual reference stations can be weighted in equation (19) to reflect the angular positions of the satellites visible at the reference stations, or an apparent noise level of the GPS receiver at each reference station.
  • Method 400 or 450 may also be modified to allow the mean clock error M k to change only slowly from one measurement epoch to the next measurement epoch by using a conventional smoothing filter. If the mean clock error M k is allowed to change by a large discrete jump, it can cause step changes in the clock corrections which then alias into the user receiver clock solution. This can cause a navigation error if the user GPS receiver employs a navigation algorithm that does not allow step changes in the receiver clock solution.
  • Method 400 or 450 may also be modified by adding a step 425 between steps 420 and 430 in method 400, as shown in FIG. 4C , or step 475 between steps 470 and 480 in method 450, as shown in FIG. 4D .
  • step 425 or 475 the computed values of the clock corrections for the individual reference stations are compared with each other, and if the clock correction for one reference station is found to differ substantially from those for the other reference stations, it can be edited or replaced with a substitute value before the average clock corrections are computed in step 430 or 470.
  • Method 400 or 450 may also be modified by forming a weighted combination of R 0 l at the right hand side of Equation (16) and/or a weighted combination of R k l - r o l at the right hand side of Equation (18) according to the elevation angles of the satellites over which the summations in the Equations are taken. Also, if the value of R k l - r o l for one satellite in equation (16) differs substantially from those obtained for the other satellites, it can be edited or replaced with an appropriate substitute value.
  • An evaluation of the spread of values of R k l - r o l entering into the summation on the right hand side of equation (18) can also be used to adjust on a site by site basis the model used to compute the tropospheric refraction effect.
  • a small stochastic adjustment could improve the response of the computed clock corrections to local weather conditions. This can be accomplished by a procedure which adjusts an overhead tropospheric refraction coefficient such that difference between R k l - r o l at different reference sites is minimized. In such a process the data from satellites with a low elevation may be weighted higher since they are more sensitive to the tropospheric refraction effects.
  • Methods, 300, 350, 400, and 450 as described above may be carried out by the main computer system 200 of the WADGPS system with the reference stations supplying the GPS pseudorange and carrier phase measurements.
  • the smoothed refraction corrected code measurements and the residuals may be computed at each of the individual reference stations by the computer system 124 coupled to the GPS receiver at the reference station. The computation results are then transmitted to the main computer system 200 for further processing.
  • the present invention provides a simple and effective method for generating GPS satellite clock corrections for a WADGPS network.
  • the computed satellite clock corrections are not affected by the ionospheric refraction effects because they are removed by the use of dual-frequency measurements.
  • the satellite orbital errors because they change much more slowly, can either be removed in a separate computational process when the WADGPS is a global DGPS network, or may simply be ignored when the WADGPS network is for a continental sized region.
  • the tropospheric refraction effect can be largely removed by modeling and if desired can be improved by the use of small stochastic adjustments included with the clock correction computation.
  • the multipath effects are removed from the code measurements by smoothing with the corresponding carrier-phase measurements. After removing these error factors, the method then provides a simple but very accurate computation of the satellite clock corrections for either continental-sized or global GPS networks.

Landscapes

  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Position Fixing By Use Of Radio Waves (AREA)
  • Electric Clocks (AREA)

Claims (26)

  1. Verfahren zur Erzeugung von Satellitenuhr-Korrekturen für ein weitreichendes GPS-Netzwerk, das eine Mehrzahl von Referenzstationen einschließlich einer Hauptreferenzstation und einer Mehrzahl von lokalen Referenzstationen aufweist, umfassend:
    für jede der Mehrzahl von lokalen Referenzstationen das Berechnen einer Lokaluhrkorrektur für jeden Satelliten, der der Hauptreferenzstation und der lokalen Referenzstation gemeinsam ist; und das Berechnen einer mittleren Uhrkorrektur für jeden Satelliten, der für die Hauptreferenzstation sichtbar ist;
    gekennzeichnet durch:
    für jede Referenzstation (120): Erhalten einer geglätteten brechungskorrigierten Codemessung für jeden Satelliten (110), der für die Referenzstation sichtbar ist, die durch Verwendung von GPS-Messungen, die vom Satelliten an der Referenzstation (300) genommen werden, gebildet wird;
    Berechnen einer Hauptuhrkorrektur für jeden Satelliten, der für die Hauptreferenzstation sichtbar ist, unter Verwendung der geglätteten brechungskorrigierten Codemessungen für die Hauptreferenzstation (410);
    für jede der Mehrzahl von lokalen Referenzstationen: Berechnen der Lokaluhrkorrektur für jeden Satelliten, der der Hauptreferenzstation und der lokalen Referenzstation (420) gemeinsam ist, unter .
    Verwendung der geglätteten brechungskorrigierten Codemessungen für die Hauptreferenzstation und die lokale Referenzstation; und
    Berechnen der mittleren Uhrkorrektur für jeden Satelliten, der für die Hauptreferenzstation sichtbar ist, durch Bilden einer Linearkombination der Hauptuhrkorrektur und der für den Satelliten (430) berechneten Lokaluhrkorrekturen.
  2. Verfahren nach Anspruch 1, wobei das Berechnen der Lokaluhrkorrekturen und das Berechnen der mittleren Uhrkorrekturen iteriert werden und die mittleren Uhrkorrekturen in einer Iterationsrunde dazu verwendet werden, die Lokaluhrkorrekturen in einer nächsten Iterationsrunde zu berechnen.
  3. Verfahren nach Anspruch 2, wobei die Linearkombination für die mittlere Uhrkorrektur gemäß den Elevationswinkeln, unter welchen die Satelliten für die Hauptreferenzstation und die lokalen Referenzstationen sichtbar sind, gewichtet ist.
  4. Verfahren nach Anspruch 1, wobei die theoretische Entfernung zwischen einer Referenzstation und einem Satelliten, der für die Referenzstation sichtbar ist, eine Anpassung für troposphärische Brechungseffekte bei den GPS-Messungen, die für den Satelliten an der Referenzstation erhalten werden, umfasst.
  5. Verfahren nach Anspruch 1, wobei die theoretische Entfernung zwischen einer Referenzstation und einem Satelliten, der für die Referenzstation sichtbar ist, eine Anpassung für Satellitenorbit-Fehler bei den GPS-Messungen, die für den Satelliten an der Referenzstation erhalten werden, umfasst.
  6. Verfahren nach Anspruch 1, wobei für jede Referenzstation und für jeden Satelliten, der für die Referenzstation sichtbar ist, die geglättete brechungskorrigierte Codemessung gebildet wird durch:
    Bilden von brechungskorrigierten Codemessungen und brechungskorrigierten Trägerphasenmessungen unter Verwendung von Zweifrequenz-GPS-Pseudoentfernungsmessungen bzw. Trägerphasenmessungen, die vom Satelliten an der Referenzstation an einer Serie von Messungs-Zeiträumen gemacht wurden, und; Glätten der brechungskorrigierten Codemessungen mit den brechungskorrigierten Trägerphasenmessungen.
  7. Verfahren nach Anspruch 1, wobei für jede Referenzstation und für jeden Satelliten, der für die Referenzstation sichtbar ist, die geglättete brechungskorrigierte Codemessung gebildet wird durch:
    Bilden einer Linearkombination von Zweifrequenz - Trägerphasenmessungen bei jeder einer Serie von Messungs-Zeiträumen und für jede Trägersignalfrequenz derart, dass die Linearkombination an den ionosphärischen Brechungseffekt bei der entsprechenden Pseudoentfernungs-Codemessung angepasst ist; Berechnen einer geglätteten Codemessung für jede Trägersignalfrequenz durch Glätten der Pseudoentfernungs-Codemessungen für die Trägersignalfrequenz mit den passenden Linearkombinationen der Zweifrequenz-Trägerphasenmessungen; und
    Kombinieren der geglätteten Codemessungen, um die geglättete brechungskorrigierte Codemessung zu bilden.
  8. Verfahren nach Anspruch 1, wobei das Berechnen der Hauptuhrkorrektur für jeden Satelliten, der für die Hauptreferenzstation sichtbar ist, umfasst:
    Erhalten eines Hauptresiduums für jeden Satelliten, der für die Hauptreferenzstation sichtbar ist, wobei das Hauptresiduum ein Versatz der geglätteten brechungskorrigierten Codemessung für den Satelliten für die Hauptreferenzstation von einer theoretischen Entfernung zwischen dem Satelliten und der Hauptreferenzstation ist; Berechnen eines mittleren Hauptempfängeruhrfehlers, basierend auf den Hauptresiduen; und
    Subtrahieren des mittleren Hauptempfängeruhrfehlers von den Hauptresiduen.
  9. Verfahren nach Anspruch 8, wobei das Berechnen des mittleren Hauptempfängeruhrfehlers das Bilden eines Mittels der Hauptresiduen über die Satelliten, die für die Referenzstation sichtbar sind, umfasst.
  10. Verfahren nach Anspruch 8, wobei das Berechnen des mittleren Hauptempfängeruhrfehlers das Bilden einer Linearkombination der Hauptresiduen, die durch die Elevationswinkel der Satelliten, die durch die Hauptreferenzstation beobachtet werden, gewichtet werden, umfasst.
  11. Verfahren nach Anspruch 8, wobei das Berechnen der Lokaluhrkorrekturen für eine lokale Referenzstation umfasst:
    Erhalten eines lokalen Residuums für jeden Satelliten, der der Hauptreferenzstation und der lokalen Referenzstation gemeinsam ist, wobei das lokale Residuum ein Versatz der geglätteten brechungskorrigierten Codemessung für den Satelliten für die lokale Referenzstation von einer theoretischen Entfernung zwischen dem Satelliten und der lokalen Referenzstation ist;
    Berechnen eines lokalen mittleren Empfängeruhrfehlers, der auf den lokalen Residuen und den Hauptresiduen basiert; und
    Subtrahieren des lokalen mittleren Empfängeruhrfehlers von den lokalen Residuen.
  12. Verfahren nach Anspruch 11, wobei das Berechnen des lokalen mittleren Empfängeruhrfehlers umfasst:
    Berechnen eines Versatzes des lokalen Residuums aus dem Hauptresiduum für jeden Satelliten, der der lokalen Referenzstation und der Hauptreferenzstation gemeinsam ist; und
    Bilden einer Linearkombination der Versätze über die Satelliten, die der lokalen Referenzstation und der Hauptreferenzstation gemeinsam sind.
  13. Verfahren nach Anspruch 12, wobei die Versätze in der Linearkombination durch Elevationswinkel der Satelliten, unter denen sie durch die lokalen Referenzstationen beobachtet werden, gewichtet werden.
  14. Computerlesbares Medium, das computerausführbare Programminstruktionen umfasst, so dass bei Ausführung ein digitales Verarbeitungssystem dazu veranlasst wird, ein Verfahren zur Erzeugung von Satellitenuhrenkorrekturen für ein weitreichendes GPS-Netzwerk, das eine Mehrzahl von Referenzstationen (120) einschließlich einer Hauptreferenzstation und einer Mehrzahl von lokalen Referenzstationen hat, durchzuführen, wobei das Verfahren umfasst:
    für jede der Mehrzahl von lokalen Referenzstationen das Berechnen einer Lokaluhrkorrektur für jeden Satelliten, der der Hauptreferenzstation und der lokalen Referenzstation gemeinsam ist; und das Berechnen einer mittleren Uhrkorrektur für jeden Satelliten, der für die Hauptreferenzstation sichtbar ist;
    gekennzeichnet durch:
    für jede Referenzstation (120): Erhalten einer geglätteten brechungskorrigierten Codemessung (300) für jeden Satelliten, der für die Referenzstation sichtbar ist, und die durch Verwendung von GPS-Messungen, die vom Satelliten an der Referenzstation genommen werden, gebildet wird;
    Berechnen einer Hauptuhrkorrektur für jeden Satelliten, der für die Hauptreferenzstation (410) sichtbar ist, durch Verwenden der geglätteten brechungskorrigierten Codemessungen für die Hauptreferenzstation;
    Berechnen der Lokaluhrkorrektur für jede der Mehrzahl der lokalen Referenzstationen für jeden der Satelliten, der der Hauptreferenzstation und der lokalen Referenzstation (420) gemeinsam ist durch Verwenden der geglätteten brechungskorrigierten Codemessungen für die Hauptreferenzstation und für die lokale Referenzstation; und
    Berechnen der mittleren Uhrkorrektur für jeden Satelliten, der für die Hauptreferenzstation (430) sichtbar ist, durch Bilden einer Linearkombination der Hauptuhrkorrektur und der für den Satelliten berechneten Lokaluhrkorrekturen.
  15. Computerlesbares Medium nach Anspruch 14, wobei das Berechnen von Lokaluhrkorrekturen und mittleren Uhrkorrekturen iteriert werden und die mittlere Uhrkorrektur in einer Iterationsrunde verwendet wird, um die Lokaluhrkorrekturen in einer weiteren Iterationsrunde zu berechnen.
  16. Computerlesbares Medium nach Anspruch 15, wobei die Linearkombination für die mittlere Uhrkorrektur gemäß den Elevationswinkeln gewichtet ist, unter welchen der Satellit für die Hauptreferenzstation und die lokalen Referenzstationen sichtbar ist.
  17. Computerlesbares Medium nach Anspruch 14, wobei die theoretische Entfernung zwischen einer Referenzstation und einem Satelliten, der für die Referenzstation sichtbar ist, eine Anpassung für die troposphärischen Brechungseffekte auf die GPS-Messungen, die an einer Referenzstation für den Satelliten erhalten wird, umfasst.
  18. Computerlesbares Medium nach Anspruch 14, wobei die theoretische Entfernung zwischen einer Referenzstation und einem Satelliten, der für die Referenzstation sichtbar ist, die Anpassung für Satellitenorbitfehler bei den GPS-Messungen, die an der Referenzstation für den Satelliten erhalten werden, umfässt.
  19. Computerlesbares Medium nach Anspruch 14, wobei für jede Referenzstation und für jeden Satelliten, der für die Referenzstation sichtbar ist, die geglättete brechungskorrigierte Codemessung gebildet wird durch:
    Bilden von brechungskorrigierten Codemessungen und
    brechungskorrigierten Trägerphasenmessungen durch jeweiliges Verwenden von Zweifrequenz-GPS-Pseudoentfernungsmessungen und Trägerphasenmessungen, die von den Satelliten an der Referenzstation bei einer Serie von Messungs-Zeiträumen erhalten werden; und
    Glätten der brechungskorrigierten Codemessungen mit den brechungskorrigierten Trägerphasenmessungen.
  20. Computerlesbares Medium nach Anspruch 14, wobei für jede Referenzstation und für jeden Satelliten, der für die Referenzstation sichtbar ist, die geglättete brechungskorrigierte Codemessung gebildet wird durch:
    Bilden einer Linearkombination von Zweifrequenz-Trägerphasenmessungen bei jeder einer Serie von Messungs-Zeiträumen und für jede Trägersignalfrequenz derart, dass die Linearkombination an den ionosphärischen Brechungseffekt bei der entsprechenden Pseudoentfernungs-Codemessung angepasst ist; Berechnen einer geglätteten Codemessung für jede Trägersignalfrequenz durch Glätten der Pseudoentfernungs-Codemessungen für die Trägersignalfrequenz mit den passenden Linearkombinationen der Zweifrequenz-Trägerphasenmessungen; und
    Kombinieren der geglätteten Codemessungen zum Bilden der geglätteten brechungskorrigierten Codemessung.
  21. Computerlesbares Medium nach Anspruch 14, wobei das Berechnen der Hauptuhrkorrektur für jeden Satelliten, der für die Hauptreferenzstation sichtbar ist, umfasst:
    Erhalten eines Hauptresiduums für jeden Satelliten, der für die Hauptreferenzstation sichtbar ist, wobei das Hauptresiduum ein Versatz der geglätteten brechungskorrigierten Codemessung für den Satelliten für die Hauptreferenzstation von einer theoretischen Entfernung zwischen dem Satelliten und der Hauptreferenzstation ist; Berechnen eines mittleren Hauptempfängeruhrfehlers, basierend auf den Hauptresiduen; und
    Subtrahieren des mittleren Hauptempfängeruhrfehlers von den Hauptresiduen.
  22. Computerlesbares Medium nach Anspruch 21, wobei das Berechnen des mittleren Hauptempfängeruhrfehlers das Bilden eines Mittels der Hauptresiduen über die Satelliten, die für die Referenzstation sichtbar sind, umfasst.
  23. Computerlesbares Medium nach Anspruch 21, wobei das Berechnen des mittleren Hauptempfängeruhrfehlers das Bilden einer Linearkombination der Hauptresiduen, die durch die Elevationswinkel der Satelliten gewichtet werden, unter denen sie durch die Hauptreferenzstation beobachtet werden, umfasst.
  24. Computerlesbares Medium nach Anspruch 21, wobei das Berechnen der Lokaluhrkorrekturen für eine lokale Referenzstation umfasst:
    Erhalten eines lokalen Residuums für jeden Satelliten, der der Hauptreferenzstation und der lokalen Referenzstation gemeinsam ist, wobei das lokale Residuum ein Versatz der geglätteten brechungskorrigierten Codemessung für den Satelliten für die lokale Referenzstation von einer theoretischen Entfernung zwischen dem Satelliten und der lokalen Referenzstation ist;
    Berechnen eines lokalen mittleren Empfängeruhrfehlers, der auf den lokalen Residuen und dem Hauptresiduum basiert; und
    Subtrahieren des lokalen mittleren Empfängeruhrfehlers von den lokalen Residuen.
  25. Computerlesbares Medium nach Anspruch 24, wobei das Berechnen des lokalen mittleren Empfängeruhrfehlers umfasst:
    Berechnen eines Versatzes des lokalen Residuums aus den Hauptresiduen für jeden Satelliten, der der lokalen Referenzstation und der Hauptreferenzstation gemeinsam ist; und
    Bilden einer Linearkombination der Versätze über die Satelliten, die der lokalen Referenzstation und der Hauptreferenzstation gemeinsam sind.
  26. Computerlesbares Medium nach Anspruch 25, wobei die Versätze in den Linearkombinationen durch Elevationswinkel der Satelliten, unter denen sie durch die lokale Referenzstation beobachtet werden, gewichtet sind.
EP04816780A 2003-07-30 2004-07-20 Verfahren zur erzeugung von taktkorrekturen für ein grossflächiges oder globales differenz-gps-system Expired - Lifetime EP1654559B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US10/630,302 US7117417B2 (en) 2003-07-30 2003-07-30 Method for generating clock corrections for a wide-area or global differential GPS system
PCT/US2004/023461 WO2005043186A2 (en) 2003-07-30 2004-07-20 Method for generating clock corrections for a wide-area or global differential gps system

Publications (2)

Publication Number Publication Date
EP1654559A2 EP1654559A2 (de) 2006-05-10
EP1654559B1 true EP1654559B1 (de) 2008-06-18

Family

ID=34103812

Family Applications (1)

Application Number Title Priority Date Filing Date
EP04816780A Expired - Lifetime EP1654559B1 (de) 2003-07-30 2004-07-20 Verfahren zur erzeugung von taktkorrekturen für ein grossflächiges oder globales differenz-gps-system

Country Status (11)

Country Link
US (1) US7117417B2 (de)
EP (1) EP1654559B1 (de)
JP (1) JP2007500845A (de)
CN (1) CN1833180A (de)
AT (1) ATE398778T1 (de)
AU (1) AU2004286519A1 (de)
BR (1) BRPI0412086A (de)
CA (1) CA2528941A1 (de)
DE (1) DE602004014509D1 (de)
ES (1) ES2308307T3 (de)
WO (1) WO2005043186A2 (de)

Families Citing this family (68)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2836997B1 (fr) * 2002-03-08 2004-06-04 Thales Sa Procede et dispositif de determination de la position relative de deux points, a base de signaux de positionnement par satellites
US7498979B2 (en) * 2006-04-17 2009-03-03 Trimble Navigation Limited Fast decimeter-level GNSS positioning
US7511661B2 (en) * 2004-01-13 2009-03-31 Navcom Technology, Inc. Method for combined use of a local positioning system, a local RTK system, and a regional, wide-area, or global carrier-phase positioning system
US7427950B2 (en) * 2004-01-13 2008-09-23 Navcom Technology, Inc. Method for increasing the reliability of position information when transitioning from a regional, wide-area, or global carrier-phase differential navigation (WADGPS) to a local real-time kinematic (RTK) navigation system
US7119741B2 (en) * 2004-01-13 2006-10-10 Navcom Technology, Inc. Method for combined use of a local RTK system and a regional, wide-area, or global carrier-phase positioning system
US7679555B2 (en) * 2004-01-13 2010-03-16 Navcom Technology, Inc. Navigation receiver and method for combined use of a standard RTK system and a global carrier-phase differential positioning system
US7248211B2 (en) * 2004-07-26 2007-07-24 Navcom Technology Inc. Moving reference receiver for RTK navigation
EP1724606A1 (de) * 2005-05-18 2006-11-22 Leica Geosystems AG Positionsbestimmungsverfahren für ein satellitengestütztes Positionierungssystem
US7609204B2 (en) * 2005-08-30 2009-10-27 Honeywell International Inc. System and method for dynamically estimating output variances for carrier-smoothing filters
US7570204B1 (en) * 2006-08-31 2009-08-04 Rockwell Collins, Inc. Generalized divergence-free carrier smoothing and dual frequency differential GPS architecture implementing the same
US7633437B2 (en) * 2006-09-22 2009-12-15 Navcom Technology, Inc. Method for using three GPS frequencies to resolve whole-cycle carrier-phase ambiguities
JP5050584B2 (ja) * 2007-03-13 2012-10-17 日本電気株式会社 測位方法、測位装置及び測位プログラム
US9128176B2 (en) 2007-06-22 2015-09-08 Trimble Navigation Limited GNSS signal processing to estimate MW biases
US20080316093A1 (en) * 2007-06-25 2008-12-25 Swensen Marvin D GPS global coverage augmentation system
FR2918763A1 (fr) 2007-07-12 2009-01-16 Thales Sa Procede de correction a la reception dans un mobile de defauts affectant a l'emission de signaux de radionavigation a porteuse a double decalage de phase
CN100437142C (zh) * 2007-07-12 2008-11-26 北京航空航天大学 基于地基增强系统的电离层延迟误差分离方法及地基增强系统
US7716615B2 (en) * 2007-08-31 2010-05-11 International Business Machines Corporation Redundant critical path circuits to meet performance requirement
US7739637B2 (en) * 2007-08-31 2010-06-15 International Business Machines Corporation Partial good schema for integrated circuits having parallel execution units
US9562975B2 (en) 2008-01-14 2017-02-07 Trimble Inc. GNSS signal processing with delta phase for incorrect starting position
US9709683B2 (en) 2008-01-14 2017-07-18 Trimble Inc. GNSS signal processing with known position for reconvergence
WO2011100690A2 (en) 2010-02-14 2011-08-18 Trimble Navigation Limited Gnss signal processing with regional augmentation message
FR2936320B1 (fr) * 2008-09-23 2012-12-28 Centre Nat Etd Spatiales Traitement de signaux de radionavigation utilisant une combinaison widelane
CN101435868B (zh) * 2008-12-09 2011-09-21 中国科学院国家授时中心 一种星钟和星历分离的矢量差分解算方法
CN101655546B (zh) * 2009-09-22 2012-02-01 西北工业大学 卫星导航直接信号参数与多径信号数目和参数的估计方法
WO2011061587A2 (en) * 2009-11-17 2011-05-26 Topcon Positioning Systems, Inc. Detection and correction of anomalous measurements and ambiguity resolution in a global navigation satellite system receiver
US8624779B2 (en) * 2010-05-18 2014-01-07 Trimble Navigation Limited Global navigation satellite system (GNSS) reference station integrity monitoring and assurance
WO2011159845A2 (en) * 2010-06-15 2011-12-22 California Institute Of Technology Annihilation method for gps integer ambiguity with residual probability scoring
US8983685B2 (en) * 2010-07-30 2015-03-17 Deere & Company System and method for moving-base RTK measurements
CN102004259A (zh) * 2010-09-17 2011-04-06 浙江大学 高灵敏度环境下基于多普勒平滑伪距的卫星导航解算定位方法
CN102565816B (zh) * 2010-12-31 2013-10-16 和芯星通科技(北京)有限公司 一种载波平滑伪距分组平滑方法和装置
CN102565813B (zh) * 2010-12-31 2013-10-16 和芯星通科技(北京)有限公司 一种通过载波平滑进行伪距观测量估计的方法和装置
US8456353B2 (en) * 2011-01-14 2013-06-04 Deere & Company Method and system for determining clock corrections
US9170335B2 (en) 2011-02-14 2015-10-27 Trimble Navigation Limited GNSS signal processing with ionosphere model for synthetic reference data
US9116231B2 (en) 2011-03-11 2015-08-25 Trimble Navigation Limited Indicating quality of GNSS position fixes
US8451169B2 (en) 2011-06-10 2013-05-28 Skytraq Technology, Inc. Method and apparatus of correcting clock drift error
US9274230B2 (en) 2011-09-16 2016-03-01 Trimble Navigation Limited GNSS signal processing methods and apparatus
CN102426372A (zh) * 2011-10-31 2012-04-25 北京中微星通电子有限公司 一种载波平滑伪距的方法及装置
CN102590840B (zh) * 2012-02-10 2013-11-06 中国测绘科学研究院 一种卫星定位载波相位差分方法
WO2013184144A1 (en) * 2012-06-08 2013-12-12 Intel Corporation Method and apparatus for correcting a reference clock of a gps receiver
JP6025430B2 (ja) * 2012-07-11 2016-11-16 三菱電機株式会社 送信装置
JP6119838B2 (ja) * 2013-02-26 2017-04-26 日本電気株式会社 状態検出方法、補正値処理装置、測位システム、および状態検出プログラム
CN103364841B (zh) * 2013-07-29 2016-01-20 中国人民解放军国防科学技术大学 一种用于航空重力测量中星座跳变误差的平滑消除方法
US10018728B2 (en) 2013-12-17 2018-07-10 Trimble Inc. Navigation satellite system positioning with enhanced satellite-specific correction information
CN105759289A (zh) * 2014-12-15 2016-07-13 国际商业机器公司 用于处理gps漂移的方法和系统
US10345448B2 (en) 2016-01-21 2019-07-09 Honeywell International Inc. Using space based augmentation system (SBAS) ephemeris sigma information to reduce ground based augmentation systems (GBAS) ephemeris decorrelation parameter
US9989644B2 (en) 2016-02-09 2018-06-05 Honeywell International Inc. Use of wide area reference receiver network data to mitigate local area error sources
CA3071876C (en) 2017-08-11 2022-10-04 Telefonaktiebolaget Lm Ericsson (Publ) Wireless device, network node and methods therein for reporting a measurement
EP3665508A1 (de) * 2017-08-11 2020-06-17 Telefonaktiebolaget LM Ericsson (Publ) Verfahren und vorrichtungen zur schätzung einer position einer drahtlosen vorrichtung unter verwendung von signalen eines globalen navigationssystems
US10473790B2 (en) 2017-11-17 2019-11-12 Swift Navigation, Inc. Systems and methods for distributed dense network processing of satellite positioning data
JPWO2019208592A1 (ja) * 2018-04-27 2021-05-20 国立大学法人静岡大学 衛星測位システム
US10969228B2 (en) * 2018-06-05 2021-04-06 Novatel Inc. Relative position navigation system for multiple moving vehicles
TWI683122B (zh) * 2018-08-27 2020-01-21 財團法人工業技術研究院 精密單點定位方法及其定位裝置與記錄媒體
US11079496B2 (en) * 2018-08-27 2021-08-03 Industrial Technology Research Institute Precise point positioning method and positioning apparatus and recording medium thereof
KR20210152549A (ko) 2019-05-01 2021-12-15 스위프트 내비게이션, 인크. 고-무결성 위성 포지셔닝을 위한 시스템 및 방법
WO2021022251A1 (en) 2019-08-01 2021-02-04 Swift Navigation, Inc. System and method for gaussian process enhanced gnss corrections generation
EP4103973A4 (de) 2020-02-14 2024-06-05 Swift Navigation, Inc. System und verfahren für rekonvergierende gnss-positionsschätzungen
US12016257B2 (en) 2020-02-19 2024-06-25 Sabanto, Inc. Methods for detecting and clearing debris from planter gauge wheels, closing wheels and seed tubes
US11480690B2 (en) 2020-06-09 2022-10-25 Swift Navigation, Inc. System and method for satellite positioning
CN116261676A (zh) 2020-07-13 2023-06-13 斯威夫特导航股份有限公司 用于确定gnss定位校正的系统和方法
US11624838B2 (en) 2020-07-17 2023-04-11 Swift Navigation, Inc. System and method for providing GNSS corrections
US11550067B2 (en) 2020-12-17 2023-01-10 Swift Navigation, Inc. System and method for fusing dead reckoning and GNSS data streams
US11733397B2 (en) 2021-07-24 2023-08-22 Swift Navigation, Inc. System and method for computing positioning protection levels
US11693120B2 (en) 2021-08-09 2023-07-04 Swift Navigation, Inc. System and method for providing GNSS corrections
WO2023167899A1 (en) 2022-03-01 2023-09-07 Swift Navigation, Inc. System and method for fusing sensor and satellite measurements for positioning determination
WO2023167916A1 (en) 2022-03-01 2023-09-07 Swift Navigation, Inc. System and method for detecting outliers in gnss observations
US12013468B2 (en) 2022-09-01 2024-06-18 Swift Navigation, Inc. System and method for determining GNSS corrections
WO2024058999A1 (en) 2022-09-12 2024-03-21 Swift Navigation, Inc. System and method for gnss correction transmission
JP7568249B1 (ja) 2024-08-30 2024-10-16 イエローテイル・ナビゲーション株式会社 衛星航法システムにおける補正情報の生成方法,補正情報を生成する情報処理装置及びプログラム

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5471217A (en) * 1993-02-01 1995-11-28 Magnavox Electronic Systems Company Method and apparatus for smoothing code measurements in a global positioning system receiver
US5477458A (en) 1994-01-03 1995-12-19 Trimble Navigation Limited Network for carrier phase differential GPS corrections
WO1996022546A1 (en) 1995-01-17 1996-07-25 The Board Of Trustees Of The Leland Stanford Junior University Wide area differential gps reference system and method
US5828336A (en) 1996-03-29 1998-10-27 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Robust real-time wide-area differential GPS navigation
US6215441B1 (en) * 1997-04-15 2001-04-10 Snaptrack, Inc. Satellite positioning reference system and method
US6266009B1 (en) 1999-03-26 2001-07-24 Rockwell Collins, Inc. Method to improve carrier smoothing of code pseudorange for global positioning and GNSS receiver implementing the same

Also Published As

Publication number Publication date
BRPI0412086A (pt) 2006-09-05
AU2004286519A1 (en) 2005-05-12
EP1654559A2 (de) 2006-05-10
CN1833180A (zh) 2006-09-13
CA2528941A1 (en) 2005-05-12
US20050024263A1 (en) 2005-02-03
US7117417B2 (en) 2006-10-03
JP2007500845A (ja) 2007-01-18
WO2005043186A3 (en) 2005-10-20
ATE398778T1 (de) 2008-07-15
DE602004014509D1 (de) 2008-07-31
WO2005043186A2 (en) 2005-05-12
ES2308307T3 (es) 2008-12-01

Similar Documents

Publication Publication Date Title
EP1654559B1 (de) Verfahren zur erzeugung von taktkorrekturen für ein grossflächiges oder globales differenz-gps-system
US8035552B2 (en) Distance dependant error mitigation in real-time kinematic (RTK) positioning
AU2008260578B2 (en) Distance dependant error mitigation in real-time kinematic (RTK) positioning
US7119741B2 (en) Method for combined use of a local RTK system and a regional, wide-area, or global carrier-phase positioning system
CA2575070C (en) Moving reference receiver for rtk navigation based on corrections calculated at reference receiver
RU2354991C2 (ru) Способ использования трех частот gps для разрешения целочисленных неоднозначностей фазы несущей
CA2557984A1 (en) Method for back-up dual-frequency navigation during brief periods when measurement data is unavailable on one of two frequencies
CN101371159B (zh) 组合使用本地定位系统、本地rtk系统与区域、广域或全球载波相位定位系统的方法
AU2011205068B2 (en) A method for combined use of a local RTK system and a regional, wide-area, or global carrier-phase positioning system
CN112415547A (zh) 卫星信号的周跳计算方法及装置

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20060223

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL HR LT LV MK

DAX Request for extension of the european patent (deleted)
17Q First examination report despatched

Effective date: 20060606

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

REF Corresponds to:

Ref document number: 602004014509

Country of ref document: DE

Date of ref document: 20080731

Kind code of ref document: P

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080618

Ref country code: FI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080618

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20080829

Year of fee payment: 5

Ref country code: ES

Payment date: 20080826

Year of fee payment: 5

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: PL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080618

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080618

Ref country code: AT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080618

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20080730

Year of fee payment: 5

Ref country code: IT

Payment date: 20080819

Year of fee payment: 5

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2308307

Country of ref document: ES

Kind code of ref document: T3

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20080827

Year of fee payment: 5

NLV1 Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080918

Ref country code: CZ

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080618

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20081118

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080618

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080618

Ref country code: RO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080618

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080731

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080618

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080918

Ref country code: EE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080618

26N No opposition filed

Effective date: 20090319

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080731

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080731

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080720

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20090720

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20100331

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20090731

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20090720

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20100202

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080720

Ref country code: HU

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20081219

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080618

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: TR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080618

REG Reference to a national code

Ref country code: ES

Ref legal event code: FD2A

Effective date: 20090721

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20090721

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080919

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20090720